Effects on community composition and function Pinus massoniana infected by Bursaphelenchus xylophilus

Time-Course Responses of Apple Leaf Endophytes to the Infection of Gymnosporangium yamadae

Apple rust, caused by Gymnosporangium yamadae, poses a significant challenge to apple production. Prior studies have underscored the pivotal role played by endophytic microbial communities, intimately linked with the host, in influencing plant diseases and their pathogenic outcomes. The objective of this study is to scrutinize alternations in endophytic microbial communities within apple leaves at different stages of apple rust using high-throughput sequencing technology. The findings revealed a discernible pattern characterized by an initial increase and subsequent decrease in the alpha diversity of microbial communities in diseased leaves. A microbial co-occurrence network analysis revealed that the complexity of the bacterial community in diseased leaves diminished initially and then rebounded during the progression of the disease. Additionally, employing the PICRUSt2 platform, this study provided preliminary insights into the functions of microbial communities at specific disease timepoints. During the spermogonial stage, endophytic bacteria particularly exhibited heightened activity in genetic information processing, metabolism, and environmental information processing pathways. Endophytic fungi also significantly enriched a large number of metabolic pathways during the spermogonial stage and aecial stage, exhibiting abnormally active life activities. These findings establish a foundation for comprehending the role of host endophytes in the interaction between pathogens and hosts. Furthermore, they offer valuable insights for the development and exploitation of plant endophytic resources, thereby contributing to enhanced strategies for managing apple rust.

Gut microbial diversity and function analysis of the final-instar larvae of Protohermes xanthodes (Megaloptera: Corydalidae)

Protohermes xanthodes (Megaloptera, Corydalidae, Protohermes), widespread species in China, is an important insects treated as food and medicine for aquaculture. In this study, the gut microbiota was investigated by 16S rRNA microbial profiling. A total of 600 Amplicon Sequence Variants (ASV) were identified, Proteobacteria and Firmicutes were the main dominant phyla, and 27 genera ran through the entire digestive tract, mainly Hafnia-Obesumbacterium (Proteobacteria), Lactobacillus and Lactococcus (Firmicutes). The PICRUSt2 functional prediction of gut microbiota showed that the foregut abundant pathways related to metabolism, environmental information processing, and genetic information processing. while the midgut had the most abundant metabolic and environmental information processing pathways, including the prominent phosphotransferase system (PTS), propionate metabolism, and β-lactam resistance. The hindgut had the weakest metabolic function, but its genetic information processing was more abundant than the foregut and midgut. Additionally, 26 strains of bacteria were isolated from the midgut microorganisms, with Firmicutes being the dominant bacteria, and some of the purified bacteria had potential probiotic and anti-pathogen functions. These findings suggest that there are differences in the microorganisms of the different gut floras of the larvae, and each flora has specific metabolic functions. This research could be used to further understand the function of gut microorganisms, explore the co-evolution of P. xanthodes and gut microorganisms, and promote healthy breeding based on gut microorganisms.

Changes in the Host Gut Microbiota during Parasitization by Parasitic Wasp Cotesia vestalis

Parasites attack the host insects and possibly impact the host-gut microbiota, which leads to provision of a suitable host environment for parasites' development. However, little is known about whether and how the parasitic wasp Cotesia vestalis alters the gut microbiota of the host Plutella xylostella. In this study, 16S rDNA microbial profiling, combined with a traditional isolation and culture method, were used to assess changes in the bacterial microbiome of parasitized and non-parasitized hosts at different developmental stages of C. vestalis larvae. Parasitization affected both the diversity and structure of the host-gut microbiota, with a significant reduction in richness on the sixth day post parasitization (6 DPP) and significant differences in bacterial structure between parasitized and non-parasitized hosts on the third day. The bacterial abundance of host-gut microbiota changed significantly as the parasitization progressed, resulting in alteration of potential functional contribution. Notably, the relative abundance of the predominant family Enterobacteriaceae was significantly decreased on the third day post-parasitization. In addition, the results of traditional isolation and culture of bacteria indicated differences in the bacterial composition between the three DPP and CK3 groups, as with 16S microbial profiling. These findings shed light on the interaction between a parasitic wasp and gut bacteria in the host insect during parasitization.